Home
Subjects
Create
Search
Log in
Sign up
Upgrade to remove ads
Only $2.99/month
Social Science
Business
Marketing Research
Research Design: Sampling and Design Dimensions
STUDY
Flashcards
Learn
Write
Spell
Test
PLAY
Match
Gravity
Quiz 2 Material
Terms in this set (37)
Total group
of interest
What is population?
Subgroup
of the larger group of interest. Representative of population
What is sample?
Procedure
for selecting a sample of the units or elements of the population.
What is sampling?
Process
by which participants in the sample are assigned to groups within the study.
What is assignment?
Probabilistic sampling (better)
Non-probabilistic sampling (not as good)
What are the two major sampling methods?
Type of sampling method.
Uses SOME form of
randomization
.
Requires that each unit have a known (often equal) probability of being selected.
Either randomly selected from population OR randomly assign subjects into groups.
What is probabilistic sampling?
Selection is systematic, NOT random.
Resembles randomization but has some sort of bias.
Type of sampling method.
What is nonprobablistic sampling?
Because each individual of the population is not truly available for study.
Actual population is the population that is accessible and is much smaller in size.
Why is target population for sampling only theoretical?
List of
available subjects
that are from an accessible population — the people you will actually have access to.
This is the source of the sample.
What is sampling frame?
Group to which researcher hopes to generalize their findings to.
Defined by clinical and demographic characteristics.
What is target population?
Potential research participants who are actually available for the study.
Defined by geographic or temporal characteristics.
Inclusion and exclusion criteria apply.
What is accessible population?
They have less variability (sampling error), therefore
approximate the population better
Why do probabilistic samples represent the population better?
1. Simple random sampling
2. Systematic sampling
3. Stratified random sampling
4. Cluster sampling
What are the types of probabilistic sampling?
Type of probabilistic sampling
Sampling done WITHOUT replacement.
Participates that are selected are NOT re-entered. Odds of subsequent selections increase for those remaining.
I.e. drawing from a hat.. (lottery system)
Random numbers table (generate list)
What is simple random sampling?
Type of probabilistic sampling
Every -nth person on a list is selected from the population using a RANDOM starting point.
Greater efficiency than simple random sampling.
Leads to achieving a sample representative of the population, HOWEVER
Greater likelihood of systematic bias occurring if it is introduced into the sampling process.
What is systematic (random) sampling?
Type of Probabilistic sampling
Used when certain subgroups (or certain characteristics) needs to be represented in an adequate number in the sample.
Can be
proportional
(distribution of that characteristic within sample closely matches what is seen in the population)
Or
Can be
non-proportional
(% of participants with that characteristic differs from that of the population)
What is stratified random sampling? What are the types?
Type of probabilistic sampling
Uses naturally occurring groups as a sampling unit when a
sampling frame does not exist
.
Provides
greater efficiency
than simple random or systematic sampling.
What is cluster sampling?
Widely used in rehabilitation research d/.t limited access of sampling frames.
No randomization
Three types:
1. Samples of convenience
2. Snowball sampling
3. Purposive sampling
Why is non-probablistic sampling more common in rehab research?
What are the types?
Type of non-probabilistic sampling
The samples are
readily available.
Accessible population can be viewed as a large sample of convenience.
What is sample of convenience?
Type of non-probabilistic sampling
Used when members of a sample are difficult to identity d/t a rare condition.
Participates asked to identity others with the same condition.
What is snowball sampling?
Type of non-probabilistic sampling
Typically used for qualitative research sampling.
Includes someone intentionally d/t their situation.
Specific reason for selecting particular participants:
information-rich cases
for in-depth study.
What is purposive sampling?
Assignment to groups.
Necessary when study design has more than one group.
Process is required for assigning particpants into groups.
Random assignment is preferred.
What is the next step after sample has been chosen?
1. Random assignment by
individual
— may lead to uneven group sizes.
2. Random assignment
by block
— ensures equal group sizes
3. Systematic assignment — counting off "every -nth"
4. Matched assignment — participants matched based on specific variables
5. Consecutive assignment —assigning individuals as they join the sample.
What are the 5 types of methods for assignments to groups?
Larger samples are more representative of their parent population.
Thus, less variability or sampling error.
Key number of applicants:
30 participants d/t Central Limit Theorem
.
How does sample size impact statistical conclusion?
Theory that 30 is the minimum number of participants needed to make valid generalizations to a larger population
AND
meets assumptions of certain statistical conclusions
What is the central limit theorem?
Purpose — reason for research
Timing of data collection — pro / retrospective
Control — manipulation or not?
What are the dimensions of design?
Document the nature of a phenomenon through systematic collection of data, then
using the data to describe the phenomenon
.
It is non-experimental.
Can be cross-sectional or longitudinal.
Data tends to be mix of
textual and numerical information
.
What is descriptive research?
Study that relies on archival records — documents
that have already been assembled
d*.
Uses content analysis.
ex: evaluation, epidemiological studies, historical or policy research.
Question is asked AFTER data has been collected.
What is retrospective study?
Study that enables the researcher to
control the data that are collected for the purpose of DESCRIBING a phenomenon
.
Question is generated BEFORE data collection.
4 basic NON-experimental data collection methods:
1. Observation
2. Examination
3. Interview
4. Questionnaire / survey
What is prospective study?
To examine correlationship (NOT causation).
Establishes r/s for future experimental research.
Scores on one variable can be predicted on another variable.
Determine reliability of measurement tools (is it reproducible?)
Validity of a measurement.
What is the purpose of analysis of relationships?
R/s can be analyzed through archival data or secondary analysis of data collected for other purpose.
How can retrospective study analyze relationships?
Allows for control over the selection of subjects and administration of measuring tools
How can prospective study analyze relationships?
Focus on whether groups or treatments are DIFFERENT in a reliable way.
What is purpose of analysis of differences?
Allows for casual comparative research after it has been done.
Assignment of groups is not under control of investigator
.
Ex. Cohort / case-control designs.
How can retrospective study help to analyze differences in relationships?
Can be experimental or non-experimental.
Experimental analysis of difference designs MUST be prospective.
Cohort designs can also be prospective.
What kind of design can a prospective analysis of difference be?
Participants randomly assigned to either experimental group or the control group.
Reports of RCT represents only ONE study.
All RCTs are "single blind". Higher level RCT may be "double blind".
This eliminates almost all bias.
RCT with
definite results
means there is a 95% confidence level.
How are true experiments effected by randomization?
Quasi-experimental: comparative, but subjects cannot be randomly assigned to groups
Repeated measures: subjects act as their own control group.
What are types of research trials WITHOUT randomization?
THIS SET IS OFTEN IN FOLDERS WITH...
Quiz 1: Overview of EB Practice
27 terms
Clinical Practice Guidelines (CPGs)
8 terms
Focused Clinical Question
16 terms
Research Design: Types and Categories
50 terms
YOU MIGHT ALSO LIKE...
6. Research Subjects
38 terms
Week 6: Population Sampling & Sampling Error
20 terms
Chapter 9 (Examining populations and samples in re…
50 terms
PSYS 053 Unit 8
50 terms
OTHER SETS BY THIS CREATOR
Laser Light, UV Radiation, Hydrotherapy, Traction…
71 terms
Electrical Stimulation for Pain Control, Tissue He…
36 terms
Research Ethics and IRB
10 terms
Electrical Stimulation for Muscle Contraction
29 terms
OTHER QUIZLET SETS
Quiz Questions
40 terms
NAEMSE Level 1 Test Review
61 terms
Bacteriology lab practical (quizzes)
56 terms
Gleim Unit 3 Subunit 3
26 terms